This invention relates generally to slide fasteners, and in particular to separable slide fasteners wherein the pair of stringers are made completely separable from each other, as for use with windbreakers and other garments. More particularly, the invention is directed to an aligning device in the slide fastener of the class under consideration whereby the fastener stringers can be coupled and uncoupled with extreme ease.
There are two well known types of separable slide fasteners, one which permits the fastener to be opened from one end only, and another known as the "two-way" or "double acting" type which permits the fastener to be opened from both ends. The former type of fasteners usually have a single slider in combination with what is generally referred to as the box and pin separable coupling, whereas the latter type of fasteners incorporate a pair of sliders arranged reversely with respect to each other on the rows of interlocking fastener elements. In either type of fasteners, it is necessary that the slider and the box member, or the pair of sliders, be held in correct alignment with each other on one of the fastener stringers during insertion or removal of the pin member on the other stringer into or out of their guide channels.
A wide variety of aligning devices have heretofore been suggested and used to this end. U.S. Pat. No. 2,069,655, for example, discloses a device wherein the slider is provided with an extension of U-shaped cross section so as to fit over part of the box member. The slider of such configuration inevitably becomes bulky in size, uneconomical, and unfavorable in appearance. French Pat. No. 735,942 and U.S. Pat. Nos. 2,728,125 and 3,583,043 are more or less identical in that they suggest devices wherein interengaging notch or notches and projection or projections are formed respectively at the opposed ends of the slider and the box member or of the pair of sliders. All these devices are unsatisfactory because the interengaging notch and projection are too conspicuous, requiring undue modification in the external appearance of the sliders. Further, according to U.S. Pat. No. 2,302,239 and Japanese Patent Publication No. 47-9388, the box member has a projecting pin portion adapted to enter a groove or grooves formed internally of the slider, but this arrangement is unapplicable to the two-way type of separable fasteners.